On Oct. 9, 1990, a container closure with tabs was first introduced by Galda; Michael P. et al. of Canadian Stanpac company. Disclosed as U.S. Pat. No. 4,961,986, with reference to FIG. 1, and “Top Tab” was the registered trademark, but the patent has expired now. Similar AU641151 was also expired. Therefore, the basic container closure structure with tabs is a conventional technology.
Galda, Michael P. et al. also proposed U.S. Pat. No. 5,433,992 on Jul. 18, 1995, wherein the use of a paper peel layer on the top tab was revealed, with reference to FIGS. 2 and 3. However, the release paper is sensitive to moisture exposure, and in particular the problems tied to uneven heating during the heat sealing step. Because the heat dispersion during sealing is uneven on the tab side and on the non-tab side, the heating of the thermo-sensitive adhesive is uneven.
On Aug. 25, 1998, JOSEPH SMELKO et al. of Canada Unipac Company proposed U.S. Pat. No. 5,975,304, which is equivalent to Australian Patent No. 717,579, ethylene-vinyl alcohol copolymer (EVOH) is used as both gas barrier and thermo-sensitive adhesive layer, also a stripping layer is added, with reference to FIG. 4.
On Feb. 7, 2003, JOSEPH SMELKO et al. ILLINOIS TOOL WORKS applied WO/2003/066465, or U.S. Pat. No. 6,902,075, titled “Container Closures”, revealed the use of nitrocellulose as the release layer material, and coated with silicone compounds as a release agent, with reference to FIG. 5.
U.S. Pat. No. 6,866,926, i.e. WO/2006/073777, titled “PULL-TAB SEALING MEMBER WITH IMPROVED HEAT DISTRIBUTION FOR A CONTAINER”, disclosed by Smelko, Joseph et al. Illinois Tool Works Company on Dec. 19, 2005, wherein a release strip and a release agent are needed, referring to FIG. 6.
ILLINOIS TOOL WORKS, INC. Smelko, Joseph et al. to applied for ROC Patent Publication No. 200706462 on Mar. 14, 2006, patent title: “CONTAINER CLOSURES”, i.e. European Patent 1,445,209, or WO/2006/099260, the trademark is Lift & Peel®, wherein a better leak-proof effect had been achieved with foam layers, referred to FIG. 7. But cellulose acetate propionate (CAP) coated with a solvent isopropanol containing silicone release agent is possessed, the solvent isopropanol emission is of course not environment-friendly. In addition, to avoid the thin PET layer crumpling up, an additional polypropylene layer is affixed to the PET layer, as a result, the laminated sheet structure is very complex. In short, organic solvents used in both the release agent and lamination process have an adverse impact on the environment.
Taiwan Forever Enterprise Company filed ROC patent applications on the following dates: 2005-10-19-ROC Patent No. M288625: Improvement on a sealed membrane structure with pulling tabs; 2005-10-26-ROC Patent No. I284616: Environment-friendly stereotyped laminated aluminum foil and the manufacturing method thereof 2006-02-14-ROC Patent No. M297931: Hidden tab structures; 2006-06-13-ROC Patent Publication No. 200800737: Destructive security closure construction; 2007-03-21-ROC Patent No. M308274: Foam plasticanti-sticking gasket; 2010-03-19-ROC Patent No. M384845: Bottle sealing gasket, but none of them mentions embossed tabs and the novel solvent-free lamination process.